Effects of quebracho on nitrification in a pilot scale extended aeration unit / J. David Eye in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXVI (Année 1981)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXVI (Année 1981) . - p 424-435 Titre : Effects of quebracho on nitrification in a pilot scale extended aeration unit Type de document : texte imprimé Auteurs : J. David Eye, Auteur ; Kenneth E. Kruse, Auteur Année de publication : 1981 Article en page(s) : p 424-435 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Tannery wastes contain high concentrations of ammonia and organic nitrogen which constitute a significant oxygen demand on receiving waters. Also, ammonia in the un-ionized form is extremely toxic to fish and other aquatic organisms. By converting the ammonia and organic nitrogen to nitrates through biological oxidation ( nitrification ) the oxygen demand and the toxicity can be reduced significantly or eliminated completely. The nitrifying bacteria are extremely sensitive to environmental conditions and careful control of nitrification systems is required. The wastes from tanneries employing the vegetable tanning process normally contain high concentrations of tannins as well as ammonia and organic nitrogen. This study was conducted for the purpose of determining if quebracho inhibits nitrification and at what concentration inhibition becomes significant. The results obtained showed that the efficienty of nitrification was reduced at all concentrations of quebracho in the influent above 100 mg/l ( quebracho in the influent ). The maximum reduction in nitrification efficiency was observed to be about 30 percent. The quebracho concentrations investigated ranged from zero to 500mg/l. At 500mg/l the observed reduction of ammonia was 93 percent. The authors believe that the reduction in nitrification was caused largely by the adverse effect of the quebracho on the clarification efficiency rather than by a direct toxic effect on the nitrifying organisms. En ligne : https://drive.google.com/file/d/1lptZFKcsC71UfqA9QuGWJmYefyMCIxIR/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17679 [article]

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